Lead brasses are very soft and therefore suitable for castings to be
worked at the lathe. Their analysis comprises, besides determinations of
copper and zinc, also that of lead and of the impurities usually occurring
in ordinary brass (iron, tin, nickel, sulphur, phosphorus, arsenic, bismuth,
etc.). The analytical methods are exactly those used for ordinary brass
Lead brasses usually contain 1-3% of lead and such impurities as are found
in common brass.
Tin brasses are used especially for making tubes, plates, valves, etc.,
for naval construction. They are analysed by the same methods as ordinary
Tin brasses contain on the average 60-62% Cu, 37-5-39% Zn and 1-1-5%
Sn. In this category fall Naval brass, I ton brass and Laveyssi&re bronze.
Manganese is introduced in small quantities into brass to increase the
strength, elasticity and hardness. The constituents of these brasses are
determined as with the complex brasses (see later).
The two types in most common use have the compositions : (i) 59-60% Cu,
40-41% Zn, traces of Mn, and (2) 58-59% Cu, 39-40% Zn, 1-8-2-2% Mn. They
are used in marine construction, especially for making propellers.
The following table gives the compositions prescribed for manganese brasses
by the American Society for the Testing of Materials and by the Technical Bureau
for Steam Plant of the United States Navy (Indus friz, 1914) :
Compositions of Manganese Brasses
American Society for the
Testing of Materials . Technical Bureau for Steam 1 Plant of U.S. Navy . /
55-60 57-60 56-68
39-45 37-40 40-42
2 I I
o-5 0-50 0-50
0-5 0-30 0-30